1. Field of the Invention
The present invention relates to electrical switching apparatus and, more particularly, to circuit breakers including a handle assembly. The invention also relates to handle assemblies for electrical switching apparatus.
2. Background Information
Circuit breakers for telecommunication systems typically are smaller than circuit breakers associated with power distribution networks. A typical telecommunication system circuit breaker measures 2.5 inches high by 2.0 inches long by 0.75 inch thick, when the circuit breaker is viewed with the operating handle extending horizontally and moving in a vertical arc. While having a reduced size, the telecommunication system circuit breaker must still accommodate the various components and devices (e.g., separable contacts; trip device; operating mechanism) associated with larger circuit breakers. Thus, while the conventional components of a telecommunication system circuit breaker may not be unique, the necessity of having a reduced size requires specialized configurations and robust components that are different than power distribution circuit breakers. This is especially true where the telecommunication system circuit breakers are used in environments wherein the circuit breaker may be expected to operate for over 10,000 operating cycles and 50 tripping cycles; however, the reduced size telecommunication system circuit breakers are typically limited to a current rating of 30 amps.
The telecommunication system circuit breaker is structured to be disposed in a multi-level rack. The rack has multiple telecommunication system circuit breakers on each level. The rack, preferably, has a spacing between the levels of 1.75 inches; however, the current structure of telecommunication system circuit breakers, as noted above, have a height of 2.5 inches. As such, users have been required to adapt the multi-level rack to accommodate the taller telecommunication system circuit breakers. Circuit breakers disposed on the rack may be coupled to associated circuits. As such, if the current is interrupted in a first circuit, either due to the circuit breaker tripping or due to a user manually interrupting the circuit, it is sometimes desirable to interrupt the current on an associated second circuit. In the prior art, a common trip bar was structured to trip two adjacent circuit breakers. That is, a single trip bar extended across two circuit breakers and, if an over current condition occurred in either circuit, the actuation of the trip device caused the trip bar to rotate thereby tripping both circuit breakers. In smaller circuit breakers which have a low trip force, the use of a common trip bar is not feasible.
Thus, while existing telecommunication system circuit breakers are small, there is still a need for telecommunication system circuit breakers having a reduced height, especially a telecommunication system circuit breaker having a height of about, or less than, 1.75 inches; the preferred spacing between levels on the rack. As the size of the telecommunication system circuit breakers are reduced further, the need for robust, yet small, components which operate in a reduced space is increased. Accordingly, there is a need for a telecommunication system circuit breaker having a reduced size and an increased operating current range.
There is a further need to resist undesired access to internal components of the circuit breaker which could result, for example, in human injury or damage to electrical components. Specifically, it is desirable to avoid access through the opening in the circuit breaker housing from which the circuit breaker handle member protrudes. Conventionally, to restrict such access, a separate generally rigid slider member has been incorporated within the opening, being coupled to the base of the handle member. The slider typically includes a hole for receiving the handle end of the handle member and is structured to engage the base of the handle member in order to move therewith while providing a barrier to resist entry through the opening. See, e.g., U.S. Pat. No. 6,225,882. Such designs require two or more separately made parts (e.g., without limitation, the slider, and the handle member) and, to ensure proper and sufficient engagement between such separate parts, a complex interface geometry is required which adds to the cost of the handle assembly.
There is, therefore, room for improvement in handle assemblies for electrical switching apparatus and in circuit breakers employing handle assemblies.